Si-Nanocrystals with Bimodal Size Distribution in Evenly Annealed SiO Revealed with Raman Scattering

The size distribution of Si-nanocrystals(Si-ncs)in evenly annealed SiO is investigated with transmission electron microscopy(TEM),x-ray diffraction(XRD),and Raman scattering.Two groups of Si-ncs with very different most probable diameters are identified,where one is>6nm and the other one is<2nm.Both of them increase gradually with increasing annealing temperature.Such a phenomenon is observed directly by TEM for samples with larger Si-ncs(>10nm)and it can be revealed clearly for all samples by Raman spectra with two components(~500cm^(-1)and~520cm^(-1)).The results of XRD show the average effect.The experimental results indicate that the common assumption of Si-nc size distribution with single most probable diameter is not always proper and the possible mechanisms are briefly discussed.

气管插管全身麻醉患者术后呼吸道感染的病原菌特点及危险因素分析

目的探讨围气管插管全身麻醉后患者发生呼吸道感染的病原菌特点和危险因素。方法回顾性分析2013年1月-2017年9月在永康市第一人民医院手术室接受全麻术的578例患者的临床资料,采用单因素和多因素分析确定气管插管全麻术后患者发生呼吸道感染的危险因素。结果 578例全身麻醉手术气管插管患者术后有65例发生呼吸道感染,感染发生率为11. 25%。65例肺部感染患者共培养出58株病原菌,其中革兰阳性菌14例,占24. 14%,革兰阴性菌42株,占72. 41%,真菌感染2例,占3. 45%。Logistic回归分析显示,年龄≥65岁、有肺部疾病病史、麻醉通气时间≥120 min、经口气管插管途径和术后延迟拔管是气管插管全麻术后患者发生呼吸道感染的独立危险因素(P <0. 05)。结论气管插管全麻术后患者发生呼吸道感染的危险因素较多,临床应针对相关危险因素采取预防措施,以降低感染的发生率。